Midterm2 Material Flashcards
(27 cards)
What is Mastitis? and what response does it have?
Mastitis is an Inflammatory reaction of the udders tissue due to bacteria, chemical, thermal and mechanical injury.
Has an inflammatory response due to the high levels of blood proteins and white blood cells in the mammary tissue and milk.
Signs of Mastitis:
- Swelling, redness and pain of udder
- Change in milk composition
Types of Mastitis:
- Subclinical; No visual signs, Milk production/composition is reduced.
- Subacute
- Acute
- Chronic
Mastitis Defence:
1st Line: Teat, Canal closed by sphincter
2nd Line: Inflammatory Response, White blood cells
3rd Line: Destruction of Milk secretory cells, Clogged alveoli
Facts about Mastitis:
Somatic Cells = Cells from the body
All milk contains leucocytes (white blood cells)
Mastitis elevates leucocytes
Manitoba Average: SCC = 306,000
LCS:
Linear Cell Score (SCC*1000) 12.5 = 0 25 = 1 50 = 2 6400 = 9
Average SCC (cells/ml)
MB = 300 (Highest) SK = 250 ON = 275
SCC Limitations:
Does not indicate pathogen
Age of cow and stage of lactation affect SCC
Types of Mastitis:
Contagious Mastitis
Environmental Mastitis
Pathogens of Mastitis:
Bacteria
Yeast and Mycoplasms
Contagious Pathogens:
Spread during Milking Via; Milking Machine
- Contaminated hands
- Contaminated Cloths
- Flies
Risk Factors for Mastitis?
- Milking Procedure
- Environment
- Characteristics of Cow
- Milking Machine
Costs of Mastitis
Reduced Milk Production: - $102/cow yr
- 11% of total milk production
- 500-1000$ per cow per year total.
- $400,000 Canadian dairy industry per year
Treating acute mastitis:
Antibiotics to milking Cows
- Pirsue
Special formula
Vaccinate
Cow hormones:
Estrogens
- Produced in follicle
- Stimulated by follicle stimulating hormone
- Role; get cow ready for conception
Progesterone
- Produced in corpus luteum and placenta
- Role; get cow ready for and maintain pregnancy
FSH (follicle stimulating hormone)
- Stimulates growth of follicle and corpus luteum
- Produced in pituitary gland
Luteinizing hormone (LH)
- Stimulates follicle and corpus luteum
- LH surge causes follicle to ovulate
Reproductive Timeline; Birth to First Calving
Puberty: 10-12 months
Duration of Cycles: Avg 21days, range 18-24days
Age at first breeding: 14-16months
Age at first calving: >24months
First Calving to Culling:
Calving to first heat: Variable 10-30day or much longer
First heat to first breeding: Voluntary waiting period of 50 days post calving
First breeding to Pregnancy: Should establish pregnancy within 3 breedings
If not new pregnancy, cow needs to be culled
Calving/parturition: after 280 days
Factors affecting conception rate:
Time of insemination
- 20% of inseminations occur when cows are not in heat
Embryonic Mortality
- High in cows (20%)
Pregnancy Rate for Cows:
- Is the % of open cycling cows intended to be bred that conceive within one cycle (21days)
PR = HD x CR
HD = heat detection rate CR = Conception rate
Manipulation of Cycles to induce estrus:
- Induce estrus on a specific time on non-cycling cows
- Puts cows in same stage of estrous cycle
Commercially Available: GnRH - Causes follicles to ovulate
PGF2a - Regresses CL
Pregnancy Detection
Rectal palpation:
- From 6wk after breeding
- Up to 100% accurate
Ultrasound
- from 3wk after breeding
- Up to 100% accurate
Milk Progesterone Test
- Milk sample at Day 21
- 95% accurate for negative diagnosis
- 75% accurate for positive diagnosis
Housing Systems Considerations:
Cow comfort
- Temp
- Humidity
- Air Exchange
- Bedding
- Flooring
- Exercise
Freestall Housing
- Most common type of housing (Especially larger herds)
- Single or Double row of stalls
- feed bunks and Alley scrapers
Bedding Choice:
- Chopped straw
- Shavings
- Sand
Feeding: Tractor or Conveyer System generally
Ventilation In Barns:
- In winter, need to get rid of stale air, but not draw too much cold air in, otherwise will fog up
- In summer, very desirable to draw air through at high speeds to keep cows comfortable and flies moving
Requirements: 15-22m3/min
